1. Field of the Invention
The present invention relates to flotation plant production beds, in which plants growing in open bottom cells of floatable flat structures are periodically floated on a liquid nutrient solution or water for supplying same upwardly into the cells for moistening and/or supplying nutrients to the plant roots. More specifically, the present invention relates to plant production beds having structures and drainage systems which minimize the amount of nutrient solution which must be stored and used in order to feed a given quantity of plants.
2. Related Art
Flotation plant production beds are known in the art. For example, U.S. Pat. No. 4,930,253 (Todd, Sr.) discloses such a system. A floatable polystyrene foam or the like plant flat is provided with an array of hollow cavities or cells in which plant growth medium is situated. Apertures at the bottom of the cavities provide communication of water or nutrient solution to the growth medium when the plant flat is floated. When the nutrient solution is drained, root growth out the apertures is prevented by the exposure to air beneath the apertures (air pruning).
In addition to the Todd, Sr. patent, other plant production systems are known. For example, U.S. Pat. No. 2,198,150 (Barnhart), U.S. Pat. No. 2,940,218 (Carter), U.S. Pat. No. 3,842,535 (Lahr) , U.S. Pat. No. 4,392,327 (Sanders) and U.S. Pat. No. 4,934,096 (Bentvelsen) provide various systems for producing plants, either in media or hydroponically. All documents referenced in this specification are incorporated herein by reference as if reproduced in full below.
Known plant production beds of the type disclosed in the Todd, Sr. patent have suffered the disadvantage that relatively large volumes of nutrient solution are required to fill the rectangular branch channels 78 of the patent sufficiently to float the plant flats. The floor slabs 80 have a planar upper surface which tilts downwardly longitudinally toward a drain at the inner end of each branch channel causing a large volume of water or nutrient solution to be required at the deeper end of the bed. Further, a relatively large amount of construction material is needed for the beds as shown in the patent. Also, the larger amount of water or nutrient solution requires a commensurately long time to fill and to drain the branch channels. Finally, larger storage containers are required for the large amount of water and nutrient solution. The present invention uses 50% of the amount of solution (and electrical power for pumping) required by the system of the Todd, Sr. patent for the same number of plant flats and also uses 30% less concrete for construction.
Therefore, there is a need in the art to provide a plant production system in which smaller volumes of nutrient solution are required.
It is therefore an object of the present invention to provide a plant production system requiring a minimal amount of construction material.
A further object is to provide a plant production system in which minimal time is required to fill and drain nutrient solution.
Yet another object of the present invention is the provision of a plant production system in which given pumping equipment is capable of servicing a larger number of plant production beds than was possible with prior art systems.
Another object is to provide a plant production system in which smaller storage tanks are required for a given number of plant production beds.